Monoazo dye.



UNITED STATES Patented May 12, 19031 PATENT OFFICE.

MYRTIL KAHN, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBENFA- BRIKEN OF ELBERFELD 00., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MONOAZO DYE.

SPECIFICATION forming part of Letters Patent No. 727,964, dated May 12, 1903.

Application filed February 16, 1903. Serial No. 143,631. (No specimens.)

NHqw sons N02,

such as ortho-amidophenol-ortho-nitropara sulfonic acid, ortho-amidophenol-para-nitroortho-sulfonic acid or the like with 1 :7-amidonaphthol having the formula:

The new dyestuffs thus obtained are brownish-black powders soluble in water with a blue color and dyeing wool from acid baths blue shades, turning black by a subsequent treatment with chromium compounds reacting as oxidizing agents. The black shades thus obtained are distinguished by great fastness to the potting process, which is a finishing process for woolen piece goods. In this process the goods are entered into boiling water and allowed to remain there until the water is cold. The goods thus assume a high degree of gloss and softness, and, according to the efieot desired, the potting may be repeated several times.

In carrying out my process practicallyl can proceed as follows, the parts being, by weight,

23.5 parts of ortho-amidophenol-ortho-nitro= para sulfonic acid having the formula:

are diazotiz'ed in the usual manner, and the resulting diaz'o compound is stirred into a solution of sixteen parts of 1 :7-amidonaphthol in caustic soda lye mixed with ice water. Care must be taken that the mass is alkaline during the reaction. After being stirred for some time the excess of caustic-soda lye is neutralized by means of hydrochloric acid, and the new dyestuff is precipitated by the addition of common salt, filtered 0d, and dried.

The new coloring-matter thus obtained is in the shape of the sodium salt a brownishblack powder soluble in water and in alcohol with a blue color and soluble in concentrated sulfuric acid of 66 Baum with a bluish-red color, turning yellowish red by the addition of a small quantity of ice, a bluish-red precipitate being obtained by the addition of a larger quantity of ice. It dyes wool from acid-bath blue shades. By subsequently treating the dyed fiber with chromium compounds reacting as oxidizing agents-such as chromates, bichromates, or the like-the shades are changed to black, distinguished for great fastness to the potting process. They also resist milling and washing'and possess a good fastness against the action of light.

Having now described my invention, what I claim is- 1. Theherein-describednewazodyestuffsderived from nitro-ortho-amidophenol sulfonic acids and 1:7-amidonaphthol which, when in a dry state, are brownish-black powders soluble in water with a blue color and dyeing wool from acid bath blue shades turning black bya subsequent treatment with chr0- mium compounds reacting as oxidizing agents, substantially as hereinbefore described.

2. The herein-described new azo dyestuff derived from ortho-amidophenol-ortho-nitropara sulfonic acid and 1 :7-amidonaphthol which, in the shape of the sodium salt, is, when dry and pulverized, a brownish-black powder soluble in water and in alcohol with a blue color and being soluble in concentrated sulfuric acid of 66 Baum with a bluish-red color turning yellowish red by adding a small quantity of ice, a bluish-red precipitate being obtained by the addition of a larger quantity of ice; dyeing W001 from acid-bath blue shades which are changed to black bya subsequent treatment with chromium compounds reacting as oxidizing agents, substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of two subscribing witnesses.

MYRTIL KAHN.

Witnesses:

OTTO Konrc; J. A. RITTERSHAUS. 

